Instructional leadership scale for high school principals: Development and validation

Principal instructional leadership (PIL) refers to the management of school curriculum, instruction, and assessment by the principal of a school. It is essential to measure the extent of the instructional leadership provided by principals and to propose means of improving instructional leadership. The principal instructional leadership scale (PILS) has been put forward to achieve these goals. In the current study, we validated the PILS on a sample of Taiwanese teachers using a multilevel approach involving expert reviews and three studies. Following two stages in confirmation of content validity by 20 experts, the initial 30-item PILS with five core concepts was subjected to discrimination analysis, exploratory factor analysis, and internal consistency reliability analysis utilizing SPSS 13.0 for Windows and AMOS 22.0 ( n = 339). This resulted in the deletion of nine items. In the second study, the individual item reliability of the remaining 21 items was examined, and the composite reliability, convergent validity, and discriminant validity confirmed the selection of the optimal model ( n = 672). The results of the third study ( n = 1438) supported metric invariance, scalar invariance, and factor variance-covariance invariance and confirmed scalar measurement invariance across genders. Finally, cross-validation analysis verified that the scale was stable and well-constructed.